1,4-dihydropyridine derivatives and their use in therapy

ABSTRACT

PCT No. PCT/FR98/00042 Sec. 371 Date Jul. 8, 1999 Sec. 102(e) Date Jul. 8, 1999 PCT Filed Jan. 12, 1998 PCT Pub. No. WO98/31680 PCT Pub. Date Jul. 23, 1998Novel 1,4-DHP of the following structures are described having better therapeutic activities in coronary diseases: wherein n and R1 are as defined in the specification.

This application is a 371 PCT/FR98/00042, Jan. 12, 1998 now WO9,831,680.

The present invention relates to novel 1,4-dihydropyridine derivatives.

Various 1,4-dihydropyridine derivatives have already been described.Thus, various esters of2,6-dimethyl-4-(3-nitrophenyl)-5-methoxycarbonyl-1,4-dihydropyridine-3-carboxylicacid and in particular the 2-[methyl(phenylmethyl)amino]ethyl esterknown under the name nicardipine, have already been described, inparticular in FR 2,218,107.

Other 1,4-dihydropyridine derivatives have moreover been described inEP-A-0,494,816, these derivatives containing in position 3 a chain ofthe type: ##STR2## in which: A represents a group chosen from the groupsof formula: ##STR3## and R₂ represents a group chosen from2,4,6-trimethoxyphenyl, 2-thienyl and phenyl groups.

The present invention is directed towards providing novel1,4-dihydropyridine derivatives which have a better therapeutic rangethan that of compounds corresponding to the formula described inEP-A-0,494,816.

A subject of the present invention is thus compounds of formula:##STR4## in which: n=1 or 2, and

R₁ is a group selected from 2,4,6-trimethoxyphenyl, 2-thienyl and2-pyrrolyl groups,

and the addition salts thereof with pharmaceutically acceptable acids.

The subject of the present invention is, more particularly,(4S,3'R)(-)N-[4-(2-thienoyl)butyl]-piperid-3'-yl2,6-dimethyl-4-(3-nitrophenyl)-5-methoxycarbonyl-1,4-dihydropyridine-3-carboxylate,(4S,3'R)(-)N-[4-(2,4,6-trimethoxybenzoyl)butyl]pyrrolidin-3'-yl2,6-dimethyl-4-(3-nitrophenyl)-5-methoxycarbonyl-1,4-dihydropyridine-3-carboxylateand (4S,3'R)(-)N-[5-(1H-2-pyrrolyl)-5-oxopentyl]piperid-3'-yl2,6-dimethyl-4-(3-nitrophenyl)-5-methoxycarbonyl-1,4-dihydropyridine-3-carboxylate,and the addition salts thereof with pharmaceutically acceptable acids.

The expression "addition salts with pharmaceutically acceptable acids"denotes salts which give the biological properties of the free bases,without having an undesirable effect. These salts can be, in particular,those formed with inorganic acids, such as hydrochloric acid,hydrobromic acid, sulphuric acid, nitric acid or phosphoric acid; acidicmetal salts, such as disodium orthophosphate and monopotassium sulphate,and organic acids.

The compounds of formula I can be obtained by reaction of the acid offormula: ##STR5## with an alcohol of formula ##STR6## in which n and R₁have the meaning given above.

The addition salts are conventionally obtained by reaction of thecompound of formula I with a pharmaceutically acceptable acid in asuitable solvent. Conversely, the bases can be obtained from additionsalts by treatment with a strong base.

The acid of formula II can be prepared as described in EP-A-0,494,816 oras described in EP-A-0,680,952.

The alcohols of formula III can be obtained by reaction of a compound offormula: ##STR7## with a chloro derivative of formula ##STR8##

The examples which follow illustrate the preparation of the compoundsaccording to the invention.

EXAMPLE 1

Preparation of (4S,3'R)(-)N-[4-(2-thienoyl)-butyl]piperid-3'-yl2,6-dimethyl-4-(3-nitrophenyl)-5-methoxycarbonyl-1,4-dihydropyridine-3-carboxylate(CRL 42249) ##STR9##

a) Preparation of 2-(5-chloropentanoyl)thiophene

16 g (0.120 mol) of aluminium chloride are introduced portionwise over15 min into a solution, maintained at about +5°, of 20.2 g (0.240 mol)of thiophene and 15.5 g (0.100 mol) of 5-chlorovaleryl chloride and themixture is stirred for 5 h at room temperature. After removal of thesupernatant by means of separating the phases by settling, the reactionmedium is taken up in 120 ml of 3N hydrochloric acid solution andextracted with chloroform.

The organic phase is washed with water and dried over dry sodiumsulphate and the solvent is evaporated off to give 16.5 g of anorange-brown oil.

Yield: 81.65%.

b) Preparation of (R)-2-[5-(3-hydroxypiperidinopentanoyl]thiophenehydrochloride

A solution of 20.3 g (0.10 mol) of the compound obtained in a) in 10 mlof acetonitrile is added over 45 min to a refluxing suspension of 8.1 g(0.08 mol) of (R)-3-hydroxypiperidine, prepared as described by H.Siertsson et al. (J. Med. Chem. 15, 1085, 1972), and 12.7 g (0.12 mol)of sodium carbonate in 20 ml of acetonitrile, and the mixture ismaintained at reflux for 1 h. The reaction medium is diluted with ethylacetate, washed with water and dried over dry sodium sulphate.

The organic phase is treated with hydrochloric isopropanol and theprecipitate is purified by crystallization from isopropanol to give 17 gof a pale pink powder.

Yield: 70%;

m.p..sub.(inst) Kofler: 143° C.;

NMR 200 MHz-TF-¹ H (CD₃ OD): 7.3-8.1 (m, 3H, thienyl-H); 4.3 (m, 1H,3-piperidyl-H); 1.6-3.7 (m, 16H, CH₂).

c) Preparation of (4S,3'R) (-)N-[4-(2-thienoyl)-butyl]piperid-3'-yl2,6-dimethyl-4-(3-nitrophenyl)-5-methoxycarbonyl-1,4-dihydropyridine-3-carboxylate

A suspension of 16.6 g (0.050 mol) of(4R)(-)-5-methoxycarbonyl-2,6-dimethyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3-carboxylicacid, 13.4 g (0.050 mol) of the product obtained in b), 3.05 g (0.025mol) of dimethylaminopyridine and 20.6 g (0.100 mol) ofdicyclohexylcarbodiimide in 400 ml of toluene is stirred for 3 days atroom temperature. The insoluble material is removed by filtration, thesolvent is evaporated off and the residue is taken up in methylenechloride and successively washed with 2N sodium hydroxide solution, 2Nhydrochloric acid solution and 5% potassium bicarbonate solution. Theorganic phase is dried over dry sodium sulphate and the solvent isevaporated off under reduced pressure.

The residue is purified by passing it through 200 g of silica (flashchromatography), eluting with a 95-methylene chloride/5-isopropanolmixture to give 18.6 g of an amorphous yellow powder.

Yield: 64%;

[α]_(D) -23 (c=1.284, MeOH);

NMR 200 MHz-TF-¹ H (CDCl₃): 7.1-8.15 (m, 7H, aromatic-H); 5.1 (s, 1H,4-dihydropyridyl-H); 4.75 (m, 1H, 3-piperidyl-H); 3.65 (s, 3H,COOCH₃);1.2-3 (m, 16H, CH₂ --), 2.3 (s, 1H, NH)

EXAMPLE 2

Preparation of(4S,3'R)(-)N-[4-(2,4,6-trimethoxybenzoyl)butyl]pyrrolidin-3'-yl2,6-dimethyl-4-(3-nitrophenyl)-5-methoxycarbonyl-1,4-dihydropyridine-3-carboxylate(CRL 42290) ##STR10##

a) Preparation of 1-(2,4,6-trimethoxybenzoyl)-4-chlorobutane

A solution of 91 g (0.384 mol) of tin tetrachloride in 112.5 ml ofbenzene is added over 1 h 30 min to a solution, maintained at about +5°C., of 50.4 g (0.3200 mol) of 1,3,5-trimethoxybenzene and 50.2 g (0.324mol) of 5-chlorovaleryl chloride in 225 ml of benzene. The mixture isstirred overnight at room temperature and the reaction medium is pouredinto 325 ml of ice-cold water and 75 ml of 12N hydrochloric acid. Theorganic phase is separated out after settling has taken place, washedwith water and dried over dry sodium sulphate.

The oily residue is purified by washing with hexane to give 84 g of awhite powder.

m.p. <50° C.;

Yield: 97.7%;

NMR 200 MHz-TF-¹ H (CDCl₃): 6.1 (s, 2H, aromatic-H); 3.9 (s, 3H,methoxy-H); 3.7 (s, 6H, methoxy-H); 3.5 (t, 2H, CH₂ Cl); 2.7 (t, 2H, CH₂CO); 1.8 (m, 4H, CH₂).

b) Preparation of(R)(-)-1-(2,4,6-trimethoxybenzoyl)-4-(3-hydroxypyrrolidino)butanehydrochloride

A solution of 28 g (0.0977 mol) of the product obtained in a) in 55 mlof toluene is added, over 1 h 15 min, to a refluxing solution of 17 g(0.1955 mol) of (R)-3-hydroxypyrrolidone in 20 ml of toluene, thereaction medium is maintained at reflux for 30 min and is diluted withethyl acetate. The mixture is washed with water and extracted withdilute hydrochloric acid solution, and the aqueous phase is basifiedwith concentrated sodium hydroxide and re-extracted with ethyl acetate.

After drying the organic phase over dry sodium sulphate, it is treatedwith hydrochloric isopropanol.

The precipitate obtained is purified by crystallization from isopropanolto give 15.2 g of a slightly mauve, water-soluble powder.

m.p..sub.(inst) Kofler: 125° C.;

Yield=41.65%;

NMR 200 MHz-TF-¹ H (CD₃ OD): 6.2 (s, 2H, aromatic-H) 3.85 (s, 3H,methoxy-H), 3.75 (s, 6H, methoxy-H); 3-3.5 (m, 6H, N--CH₂); 2.8 (t, 2H,CH₂ --CO); 1.6-2.1 (m, 6H, CH₂).

EXAMPLE 3

Preparation of(4S,3'R)(-)N-[5-(1H-pyrrol-2-yl)-5-oxopentyl]piperid-3'-yl2,6-dimethyl-4-(3-nitrophenyl)-5-methoxycarbonyl-1,4-dihydropyridine-3-caroxylate(CRL 42547) ##STR11##

a) Preparation of 2-(5-chloropentanoyl)-1H-pyrrole

A solution of 26.7 g (0.200 mol) of aluminium chloride and 31 g (0.200mol) of 5-chlorovaleryl chloride in 200 ml of 1,2-dichloroethane isadded slowly to a solution of 13.4 g (0.200 mol) of pyrrole in 250 ml of1,2-dichloroethane. The reaction medium is stirred for 2 h at roomtemperature and is poured onto ice-cold hydrochloric acid. Afterextraction with methylene chloride, a red-brown oil is obtained.

This product is purified by flash chromatography on silica gel 60 andeluted with a 90-hexane/10-ethyl acetate mixture, to give 15 g of aslightly orange-coloured oil.

Yield=40.4%;

NMR 200 MHz-TF-¹ H (CDCl₃): 6.2-7.1 (m, 3H, pyrrole-H); 3.5 (t, 2H, CH₂Cl); 2.8 (t, 2H, CH₂ --CO); 1.8 (m, 4H, CH₂).

c) Preparation of(4S,3'R)(-)N-[4-(2,4,6-trimethoxybenzoyl)butyl]pyrrolidin-3'-yl2,6-dimethyl-4-(3-nitrophenyl)-5-methoxycarbonyl-1,4-dihydropyridine-3-carboxylate

A solution of 9.9 g (0.048 mol) of dicyclohexylcarbodiimide in 60 ml oftoluene is added to a suspension of 8 g (0.024 mol) of(4R)-5-methoxycarbonyl-2,6-dimethyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3-carboxylicacid and 8.1 g (0.024 mol) of the product obtained in b) in base form,in the presence of 1.5 g (0.012 mol) of dimethylaminopyridine in 140 mlof toluene. The mixture is stirred for 4 days at room temperature, theprecipitate is removed by filtration and the solvent is evaporated offunder reduced pressure. The residue is taken up in chloroform and washedwith 2N sodium hydroxide, 2N hydrochloric acid and 5% potassiumbicarbonate solution.

After drying over dry sodium sulphate and evaporation of the solvent,the residue is purified by flash chromatography on a column of silicawith a 97.5-methylene chloride/2.5-isopropanol mixture, to give 8.8 g ofa water-insoluble yellow foamy powder.

Yield: 56.3%;

Total yield 22.9%;

[α]_(D) -1.2 (c=1.252, MeOH);

NMR 200 MHz-TF-¹ H (CDCl₃): 7.2-8.1 (m, 4H, aromatic-H); 6.1 (s, 2H,aromatic-H); 5.1 (m 2H, 4-dihydropyridyl-H; 3-pyrrolidinyl-H); 3.8 (s,3H, methoxy-H); 3.7 (s, 6H, methoxy-H); 3.6 (s, 3H, COOCH₃); 2.3 (s, 6H,CH₃), 1.4-2.9 (m, 14H, CH₂).

b) Preparation of 2-[5-(3-hydroxypiperidino)-pentanoyl]-1H-pyrrolehydrochloride

A solution of 16.5 g (0.089 mol) of the product obtained in a) in 20 mlof acetonitrile is added, over 1 h, to a refluxing suspension of 8.9 g(0.089 mol) of (R)-3-hydroxypiperidine, 18.4 g (0.1335 mol) of potassiumcarbonate and 2.2 g (0.01335 mol) of potassium iodide in 18 ml ofacetonitrile, and refluxing is continued overnight. The reaction mediumis diluted with ethyl acetate, washed with water and extracted with 2Nhydrochloric acid solution. The aqueous phase is basified withconcentrated sodium hydroxide and the insoluble material is extractedwith ethyl acetate. The organic phase is treated with hydrochloricisopropanol to give 20.2 g of a green-grey powder.

m.p._(inst) (Kofler)=188° C.;

Yield=79.2%;

NMR 200 MHz-TF-¹ H (CDCl₃): 6.2-7.1 (m, 3H, pyrrole-H); 4.3 (m, 1H,CH--OH); 3-3.5 (m, 6H, N--CH₂); 2.8 (t, 2H, CH₂ --CO); 1.6-2 (m, 8H,CH₂)

c) Preparation of(4S,3'R)(-)N-[5-(1H-pyrrol-2-yl)-5-oxopentyl]piperid-3'yl2,6-dimethyl-4-(3-nitrophenyl)-5-methoxycarbonyl-1,4-dihydropyridine-3-carboxylate

A solution of 15.7 g (0.076 mol) of dicyclohexylcarbodiimide in 125 mlof toluene is added to a suspension, maintained under a nitrogenatmosphere, of 12.6 g (0.038 mol) of(4R)-(-)-5-methoxycarbonyl-2,6-dimethyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3-carboxylicacid and 9.5 g (0.038 mol) of the product obtained in b) in base form,in the presence of 2.3 g (0.019 mol) of dimethylaminopyridine in 250 mlof toluene. The mixture is stirred for 7 days at room temperature, theprecipitate is removed by filtration and the solvent is evaporated offunder reduced pressure. The residue is taken up in methylene chlorideand washed with 2N sodium hydroxide, 2N hydrochloric acid and 5%potassium bicarbonate solution.

After drying over dry sodium sulphate and evaporation of the solvent,the residue is purified by flash chromatography on a column of silicawith a 95-methylene chloride/5-isopropanol mixture, to give 14 g of awater-insoluble yellow foamy powder.

Yield: 65.3%;

Total yield=20.9%;

[α]_(D) -2.37 (c=1.332, MeOH);

NMR 200 MHz-TF-¹ H (CDCl₃): 7.3-8.1 (m, 4H, aromatic-H); 6.2-7.1 (m, 3H,pyrrole-H); 5.1 (s, 1H, 4-dihydropyridinyl-H); 4.8 (m, 1H,2-piperidyl-H); 3.6 (s, 3H, COOCH₃); 1.3-2.8 (m, 16H, CH₂), 2.3 (s, 6H,CH₃).

Pharmacological results demonstrating the advantageous properties of thecompounds of the invention will be given below.

1) Anticalcium activity by measuring the affinity for the DHP sites ofrat cardiac ventricles

The affinity of the compounds for the DHP sites of cardiac ventricles ismeasured from a membrane preparation of the receptors, this preparationbeing obtained after dissecting the ventricles, homogenization and thendouble-centrifugation (48,000×g; 15 min., +4° C.).

These membrane preparations are placed in contact with the specificradioactive ligand (+)-[³ H]-PN 200-110 and the test compound, atdifferent concentrations. The suspension is stirred for 30 minutes at atemperature of 30° C. The reaction is then stopped by filtration using aHarvester-type system. The filter is introduced into a counting flaskcontaining scintillation liquid. The radioactivity present on eachfilter is then measured by counting in a β-counter with liquidscintillation.

The intensity of the binding to the membrane receptors is defined by the(molar) concentration of the test compound which is needed to displace50% of the amount of the specific ligand (+)-[³ H]-PN 200-110 preboundto the DHP sites. This concentration is the IC₅₀ concentration.

The results, expressed as IC₅₀, are given in the following table:

    ______________________________________                                               Compound                                                                              IC.sub.50                                                      ______________________________________                                               Example 1                                                                             1.5 × 10.sup.-8                                            Example 2 7.8 × 10.sup.-9                                             ______________________________________                                    

2) Anticalcium activity by measuring the KCl-mediated antagonism of thecontraction of isolated rat aorta

The technique employed uses a ring of arterial vascular tissue takenfrom rat thoracic aorta and then kept alive in aerated bicarbonatedKrebs buffer, and subjected to an initial tension of 2 g. Theintroduction of potassium chloride KCl (in a volume of 300 μl) at aconcentration 5×10⁻² M.l⁻¹ into the Krebs buffer bath generates asustained contraction whose amplitude (isometric tension) is antagonizedby the addition of a solution of the test compound of increasingconcentrations, each addition being made every 5 minutes. The molarconcentration of the test compound which reduces by 50% the maximumcontraction observed in KCl is then calculated. This concentration isthe 50% inhibitory concentration (or IC₅₀).

The results, expressed as ICso, are given in the following table:

    ______________________________________                                               Compound                                                                              IC.sub.50                                                      ______________________________________                                               Example 1                                                                             1.3 × 10.sup.-7                                            Example 3 1.6 × 10.sup.-7                                             ______________________________________                                    

3) Hypotensive effect in conscious, spontaneously hypertensive rats

The animals receive increasing doses of compound every 90 minutes viathe gastric route.

The hypotensive effect is evaluated by means of the percentage ofmaximum reduction of the average arterial pressure after administrationof each dose.

    ______________________________________                                                 Dose mg/kg                                                           Compound   3             +10    +30                                           ______________________________________                                        Example 1  0%            -22%   -45%                                            Example 3 -12% -21% -54%                                                    ______________________________________                                    

4) Effect on the coronary output of anaesthetized dogs

The animals receive increasing doses of compound every 30 minutes viathe intravenous route. The effect on the coronary output is evaluated bymeans of its percentage of maximum variation after each dose.

    ______________________________________                                                Compound                                                              Dose μg/kg                                                                           Example 1    Example 2                                                                              Example 3                                     ______________________________________                                        5         12%          +16%     +7%                                             +10 +28% +14% +30%                                                            +20 +56% +34% +59%                                                            +40 +72% +78% +76%                                                            +80 +81% +68% +84%                                                            +160 +67% +59% +84%                                                           +320 +64% +33% +59%                                                         ______________________________________                                    

5) Therapeutic index

The therapeutic index is defined as being the ratio between the minimumarrhythmogenic dose and the dose which increases the basal coronaryoutput by 50% (this dose is referred to hereinbelow as the "dose whichis active on the coronary output").

The minimum arrhythmogenic doses were determined for each compound onanaesthetized dogs via the intravenous route and the arrhythmogenicdose/dose which is active on the coronary output ratio (therapeuticmargin) was determined.

The results obtained are given below:

    ______________________________________                                                         Arrhythmogenic dose/                                            dose which is active on                                                      Compound the coronary output                                                ______________________________________                                        Example 1        640/20 = 32                                                    Example 2 640/40 = 16                                                         Example 3 640/20 = 32                                                         Example A (comparative) 640/640 = 1                                           Example B (comparative) 640/640 = 1                                         ______________________________________                                    

The comparative compounds A and B are compounds which differ,respectively, from the compounds of Examples 1 and 2 only in the lengthof the chain (3 carbons instead of 4 carbons between the nitrogenousheterocycle and the ##STR12## group).

A subject of the present invention is also therapeutic compositionscomprising, as active principle, a compound of formula I or one of theaddition salts thereof with pharmaceutically acceptable acids.

The therapeutic compositions according to the invention can beadministered to man or animals orally or parenterally.

They can be in the form of solid, semi-solid or liquid preparations. Asexamples, mention may be made of tablets, gel-capsules, suppositories,injectable suspensions or solutions, as well as delay forms andslow-release implanted forms.

In these compositions, the active principle is generally mixed with oneor more common pharmaceutically acceptable excipients which are wellknown to those skilled in the art.

The amount of active principle administered depends, needless to say, onthe patient being treated, the route of administration and the severityof the complaint.

What is claimed is:
 1. Compounds of formula: ##STR13## in which: n=1 or2, andR₁ is a group selected from 2,4,6-trimethoxyphenyl, 2-thienyl and2-pyrrolyl groups, and the addition salts thereof with pharmaceuticallyacceptable acids.
 2. Compound according to claim 1, which is(4S,3'R)(-)N-[4-(2-thienoyl)butyl]piperid-3'-yl2,6-dimethyl-4-(3-nitrophenyl)-5-methoxycarbonyl-1,4-dihydropyridine-3-carboxylate,and the addition salts thereof with pharmaceutically acceptable acids.3. Compound according to claim 1, which is(4S,3'R)(-)N-[4-(2,4,6-trimethoxybenzoyl)butyl]pyrrolidin-3'-yl2,6-dimethyl-4-(3-nitrophenyl)-5-methoxycarbonyl-1,4-dihydropyridine-3-carboxylate,and the addition salts thereof with pharmaceutically acceptable acids.4. Compound according to claim 1, which is(4S,3'R)(-)N-[5-(1H-2-pyrrolyl)-5-oxopentyl]piperid-3'-yl2,6-dimethyl-4-(3-nitrophenyl)-5-methoxycarbonyl-1,4-dihydropyridine-3-carboxylate,and the addition salts thereof with pharmaceutically acceptable acids.5. Process for preparing a compound according to claim 1, comprising thereaction of the acid of formula: ##STR14## with an alcohol of formula##STR15##
 6. A pharmaceutical composition comprising an effective amountof the compound according to claim 1 in combination with apharmaceutically acceptable carrier.
 7. A pharmaceutical compositioncomprising an effective amount of the compound according to claim 2 incombination with a pharmaceutically acceptable carrier.
 8. Apharmaceutical composition comprising an effective amount of thecompound according to claim 3 in combination with a pharmaceuticallyacceptable carrier.
 9. A pharmaceutical composition comprising aneffective amount of the compound according to claim 4 in combinationwith a pharmaceutically acceptable carrier.